Project Management and Design of a Space Cryostat
Preamble
In recent years, Oxford Instruments have been developing for
the European Space Agency (ESA) a device for precision measurement of the force
of gravity. The device, a Superconducting Gravity Gradiometer (SGG) operates at
liquid helium temperature. The intention is that this device will map the
gravity field of the earth with a degree of spatial accuracy and measurement
precision far exceeding current data. This information is of importance to
studies of ocean circulation currents (modified by global warming), vulcanology,
and mineral prospecting.
The cryostat design is particularly critical: although cryostats for space use are
well known, the SGG application gives particular difficulties. The most
significant of these is that the closest mass to the SGG is the liquid helium.
As the helium is consumed during the mission, the remaining helium in the vessel
moves in an unpredictable and physically unstable way in the micro-gravity
environment of space. This gravity noise signal destroys the utility of the
instrument.
Work programme
Technology Enterprise took technical and management responsibility for the cryogenic aspects of the
project, working with the Oxford Instruments team, with Mullard Space Science
Labs (MSSL), Alenia Spazio and the University of Trenta.
Technology Enterprise was also engaged to co-ordinate and
write the final report to Alenia Spazio and ESA for the whole work package. This
involved coordinating input from several sites within the Oxford Instruments
group and
Mullard Space Science Labs (MSSL). It also involved understanding and
summarising the results of several highly mathematical interim or internal
technical reports for incorporation into the final document. The final document
served two purposes: first, it provided a succinct technical summary of the work
programme; second it provided a credible marketing document for subsequent
contracts between ESA and Oxford Instruments.
This highly successful assignment was carried out on schedule
and to cost.
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